The present invention relates to a process and apparatus for for making a molded article.
A method of making a molded article from a nonflowable mixture of chip and fiber material and thermally hardenable binder is known. In this process the mixture is pressed in a press with a mold closed on all of its sides and is hardened therein. A portion of the heat energy required for hardening is supplied by heated gas or steam fed to the mixture during the pressing.
This type of process has been described in German Patent Document DE-C 1 284 624. In this process break off of particles from the prepressed body must be avoided, because during the hot pressing step these particles then clog the ducts through which the steam and gases arising in the pressed mass are conducted away or through which hot gases are fed into the interior of the press mold. To solve this problem in the known method a plurality of recess are pressed into the pressed material in prepressing. These recesses are distributed over the surface of the pressed material at least one one of its sides.
On the other hand the present invention deals with a process for making a molded article from a nonflowable mixture, in which the molded body is pressed in a hot pressing process from the mixture. Indeed a feature of this process should be the rapid and uniform delivery of gas or steam to the closed mold, so that the pressing and hardening time is reduced to a minimum.